I won't compound by adding my woes but I feel your words like knives in my chest. I can imagine myself posting something very similar in the future and this is the advice I hope someone would give me, and it's going to ring as complete BS because it always does;
Therapy isn't about fixing you. Nobody walks in to a psychologist's office one day and walks out "cured" because for the most part those don't exist. What you get are a set of tools, unique and catered to specifically you. There's no shame in learning something new, and sometimes it's worth it just to have somewhere to walk in, verbally throw up everything on your mind, have that one person just say "Wow. That sucks.", and let you cry.
As far as we all come with our physical health, maintaining mental health will be a long and personal ordeal of its own. Corny as it is and as much as I want to smack myself in the face for saying it, you can get through this, you absolutely can.
To end on a light note, my absolute favourite thing circulating Facebook at the moment is a meme of Oscar the Grouch saying "Just because you're trash doesn't mean you can't do great things. It's called garbage can, not garbage cannot." When I do inevitably feel the way you feel right now I really hope that while calling myself trash in the mirror I'll remember that "trash can". <3
I really hope you're feeling better soon.